The present invention relates to a tool for forming a groove in a workpiece. More particularly, the invention relates to a tool which may be utilized to form a precisely positioned compression ring seat in a cylinder head such as may be found in certain types of diesel engines.
As is well known, diesel engines utilize the principle of very high compression to generate combustion of the fuel-air mixture within the engine cylinder.
In several series of the engines produced by Mack, in addition to a flat head gasket of the normal type, a lip extends above the engine block about each cylinder in order to force a compression ring to seat in an aligned groove in the cylinder head. Since the compression ring is relatively soft metal, as the cylinder head bolts are tightened, the lip will force the ring to compress into the groove and expand so as to provide a better compression seal than might otherwise be available.
After a normal period of use, the head of a diesel engine must be removed for normal engine repairs. When this is accomplished, the head must be resurfaced, at least partially, in order to get rid of pitting, warpage, etc. Resurfacing of the cylinder head significantly alters the depth of the groove and, in some cases, eliminates the groove altogether. As a result, whenever such work is accomplished, the groove must be reformed or recut in the cylinder head in order to accept a new compression ring when the head is replaced on the engine block.
Tools are currently used for providing or recutting such grooves, but they are very difficult to use, employ an alignment device which is not sufficiently accurate and steadying for the tool to ensure a proper positioning of the groove, and, further, require the use of a plurality of different grooving tools for operating on different engines. For example, one tool must be provided for six-cylinder engines and a different tool for eight-cylinder engines. In either case, it is rather difficult and requires a good deal of skill, to keep the tool properly aligned with the cylinder head in relation to the cylinder openings. If a mistake is made in forming the groove, or if the tool cannot be properly fixed in position while the cutting is being accomplished, the cylinder head may be at least temporarily damaged, resulting in the loss of that engine and the equipment driven by it until the head is again resurfaced and regrooved or a new head is procured.